Curved flow lines for well bores



Feb. 6, 1968 M, RAULINS 3,367,421

CURVED FLOW LINES FOR WELL BORES 2 Sheets-Sheez 1 if fAfl/eA/roe.

050265 M. Bzw/L m/s 595/ W @rMen/EH Feb. 6, 1968 G. M. RAULINS CURVED FLOW LINES FOR WELL BORES fM/E/vra/e @Trona/EV.

2 Sheets-Sheet P Filed Aug. G, 1965 United States Patent O 3,367,421 CURVED FLOW LINES FOR WELL EURES George M. Raulins, Houston, Tex., assigner to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Filed Aug. 6, 1965, Ser. No. 477,698 8 Claims. (Cl. 166-153) ABSTRACT F THE DISCLOSURE Flow line apparatus, including a tubular elbow section for incorporation in a flow line and having terminal portions of circular cross-section, an arcuate 90 degree intermediate portion of uniform oblong cross-section, and a tapered portion between each terminal portion and intermediate portion, in combination with an articulated tool assemblage to be pumped through the elbow section and having forward and rearward piston units spaced apart su'lciently so that the forward piston unit will be slidably sealed in a forward terminal portion or adjacent circular pipe before the rearward piston unit leaves the rearward terminal portion and enters the adjacent tapered portion.

The present invention relates to well bore apparatus, and more particularly to flow lines through which access is gained to subsea Well bores from surface locations.

Oil and gas wells have been completed in waters ex- Ceeding 300 feet in depth. Such wells cannot, as a practical matter, be completed in a normal manner, but require well heads at the bottom of the sea with ow and control lines extending from the well head to gathering and control stations.

If rigs or service units were to be used directly over the well head in performing remedial work in ocean floor completed well bores, the cost would be prohibitively high. To eliminate such high cost, well heads have been designed that allow remedial and service operations to be performed by having flow lines extend to the Well head which are connected to one or more tubular strings in the well bore. A desired tool is pumped into a flow line, which has one or more curved or bend portions, and into a tubing string in the well bore. Such tool may also be reversely pumped out of the tubing string and through the ilow line back to the surface. In the past, the curved portions of the ow line have had a radius of curvature of not less than ve feet. The tools that can be pumped through such curved portions have been limited in the length of each of their straight and unknuckled portions, requiring them to be of special and limited design, of greater cost, and relatively undependable. Moreover, the comparatively large radius of the curvature makes the curved flow line portions overly long and of decreased strength and stability.

Accordingly, it is an object of the present invention to provide a curved flow line portion having a comparatively small radius of curvature, enabling it to` be relatively short, compact and of increased structural strength, and yet capable of permitting tools to be pumped through it having straight and unknuckled portions of substantially greaterv length'.

Another object of the invention is to provide a curved flow line portion through which many standard tools can be pumped without modification, such tools, as a rule, possessing greater dependability than tools specially designed for pumping through curved flow lines.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is ,to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best dened by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section through .a device embodying the invention connected in a flow line cornmunicating with a subsea well bore;

FIG. 2 is an enlarged cross-section taken along the line.

2--2 on FIG. l;

FIG. 3 is an enlarged cross-section taken along the line` 3 3 on FIG. 1;

ocean floor F. One or a plurality of tubular strings H, J- are connected to the well head and extend downwardly therefrom, being suitably related to a wellpacker K anchored in packed-off condition in the well casing. The lower end of one of the tubing strings J may be connected to the other tubing string H below the well packer, The other tubing string H may be used for producing from a formation in the well bore below the packer K, the well.

production passing through a ow line M running to the surface of the water or to the shore. This ow line may include one or more curved portions or bends P, one. ofV

which is connected to the tubing string H, with the other end of such curved flow line portion being connected to another section R of the ow line. The curved portions P are used to enable tools to be pumped down through the ow line M and into the tubular string H and reversely pumped therefrom when desirable remedial or other types of work is to be done in the tubing string.

Heretofore, the curved or bend portion of` the flow line has had a radius of curvature of not less than ve feet, and, in a typical case, the inside diameter of.the flow line would be two inches. As a practical matter, only tools, having straight portions of comparatively short lengthcould be pumped through such a ow line. As illustratedl by way of example in FIG. 5, an assemblage of articulated tools 10, 11, 12, 13 can be pumped through the flow line and into the tubing string or` reversely from the tubing` string back out through the flow line, and includes a for.

ward power or piston unit 12 and a rearward power or piston unit 10, each of which is connected by a knuckle joint 14, or other pivoted connection, with the upper and lower ends of a suitable tool 11, which might 4be a set of jars. The forward piston or power unit 12 is connected by a knuckle or hinge joint 14 with a suitable tool 13,A

such as a pulling tool, thatl is to be connected to another device in the tubular string for the purpose of becoming` secured thereto, enabling reverse pumping of the unit upwardly through thetubing string to pull such other device upwardly with it and through the ow line to alocation out of the water. As a practical matterLit is found that each straight portion of the articulated assemblage of the tools could only have a length that did not exceed 111/2 inches, with the maximum diameter of each section being 1% inches. At least one of the piston units 10, 12 would seal againstvthe inner wall of the llowline, including its curved portion P1, so that a pressure differential across the piston unit could force or pump the entire assembly ahead of the fluid under pressure into the flow line M and tubing string H, or out of such tubing string and ow line. Because of the short length of the straight section of each one ofv these tools, a special design of equipment is necessary, which is rather costly. It would be preferable if prov en tools of a standard type could be used without modifcation, that is, tools that are normally used in well bores that do not have to pass through any curved or bend portion of a low line. In addition, the curved flow line section P1 of a five foot radius in a bend extending through 90 degrees of arc is rather lengthy and comparatively flexible and, therefore, becomes subject to damage, particularly when located under water.

In lieu of the minimum live foot radius of curvature bend illustrated in FIG. 5, a curved or bend portion P of a flow line is used having a much smaller radius of curvature. This curved section will permit tools to be passed through it having straight portions of much greater length than can be passed through the curved portion of far greate-r radius of curvature referred to above. As shown in FIGS. 1 to 4, a 9() degree elbow section P is illustrated that has cylindrical portions 21, 22 at its opposite ends for connection in a known manner to an adjacent straight portion R of a ow line or of a tubing string H extending into the well bore, or for connection to ad jacent portions of a flow line of any appropriate contiguration. The main curved portion 23 of the section P is oval or oblong in cross-section, having a major diameter 24 in the plane of the curved portion that is much greater than its minor diameter 25, which is at right angles to such plane. The minor diameter or width 25 of the oval portion may conform to the inside diameter of the tubing R, H on opposite sides of the bend section P. The curved outer side 26 of the curved section may extend through an arc of about 90 degrees and merges into a straight cylindrical outer portion 27 extending to each adjacent section of tubing R, H. The curved inner side 28 of the bend section merges at each end into a tapered portion 29 which inclines toward the cylindrical end 21 or 22 of the curved section.

By way of example, assuming the tubing R, H attached to each end 21, 22 of the curved section P is two inches in diameter, the minor diameter 25 of the oval cross-sectional portion 23 of the curved section would also be two inches and the major diameter 24 may be tive inches. With this proportion of parts, an articulated assemblage of tools 30-33 can be pumped down the tubing string R and through the curved section P, with each straight portion of the assemblage being much longer than is possible with the live-foot radius of curvature bend illustrated in FIG. 5. As an example, each straight section of the articulated assembly of devices can be 24 inches in length.

As shown in FIG. 1, a power unit 31 or 32 may be hingedly attached to each end of a set of jars 30, that may be 24 inches in length, and each power unit at its end remote from the jars will include piston or sealing elements, such as oppositely facing cup-type packings 40, 41, adapted to slidably seal along the wall of the tubing strings M, H. One of the power units 31 may have a suitable tool 33, such as a pulling tool, hingedly secured thereto, and this pulling tool may, if desired, also have a length of the order of about 24 inches in the specic example of curved section given above. The overall distance between the piston units or packings 40, 41 of the two power units 31, 32 is such that one set of the packing or sealing elements 40, 41 will be in a two-inch diameter tubing section R or H at any one time during shifting of the articulated device through the curved section P. Assuming that the assemblage is to be pumped down through the flow line M and into the tubing string H, fluid pressure imposed in the flow line will force the assemblage 30-33 ahead of it, and it will pass into the curved section P, shifting therethrough. Before the pistons 40, 41 of the trailing unit 32 leave the cylindrical portion of the ow line M and enter the enlarged oblong portion 23 of the curved section, the pistons 40, 41 of the leading unit 31 will have already left the oval portion of the curved portion P and be disposed in the cylindrical portion of the tubing H therebelow, which will then allow any fluid that might bypass the upper piston unit to engage the lower piston unit and continue moving the assemblage through the curved section P and completely into the tubing string H, through which it will pass downwardly to some other device T in the tubing string H to be actuated by the pulling tool 33. During such pumping of the assemblage of tools through the flow line and down through the tubing string H, the fluid in advance thereof can pass into the other tubing string J and back up to the top of the well bore and through a ow line S to the surface.

When it is desired to retrieve the assemblage of tools 30-33, and whatever device T might be connected to the pulling tool, fluid under pressure is pumped through the other flow line S and tubing string J, passing into the lower portion of the production tubing string H and acting on the packings of the lower unit 31 to force the assemblage and the device T connected thereto upwardly through the tubing string H, the assemblage then moving into the curved section P of the ow line M. Before the lower piston unit enters the oval or non-circular portion 23 of the curved section P, the pistons 4t), 41 of the unit 32 thereabove will have already moved out of such oval portion and into the cylindrical portion R of the iiow line M, whereupon the fluid under pressure can then bypass around the lower piston unit, the fluid under pressure moving through the curved section and acting upon the upper piston unit to continue moving the assemblage through the curved section and through the ow line M to the surface.

It is apparent that with the provision of the oblong pas sage through the curved section 23, an assemblage of tools having much longer straight portions than heretofore used can be pumped through flow line sections. Such tools of longer length include standard tools of proven ability and dependability to accomplish their desired objectives in the well bore. In other words, special tools are not necessary for pumping through curved sections of flow lines. It is further to be noted that the curved section or elbow P of the flow line is much shorter and more compact than the prior five-foot minimum radius of curvature of curved section P1, and that, because of its shortness and compactness, it has less flexibility and can have greater structural strength.

I claim:

1. In well apparatus: a ow line including a tubular elbow section having terminal portions at its opposite ends adapted for connection to adjacent members and a curved intermediate portion of oblong cross-section; an assemblage of articulated devices movable through said elbow section, said assemblage including a forward piston unit, a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably` seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward piston unit can move out of the other terminal portion.

2. In well apparatus: .a flow line including a tubular elbow section having terminal portions at its opposite ends of substantially circular cross-section and a curved intermediate portion of oblong cross-section, the larger dimension of said oblong intermediate portion lying in a plane of said elbow section passing through said terminal and intermediate portions; an assemblage of articulated devices movable through said elbow section, said assemblage including a forward piston unit, a rearward piston unit, a

tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward piston unit can move out of the other terminal portion.

3. In well apparatus: a ow line including a tubular elbow section having terminal portions at its opposite ends of substantially circular cross-section, a curved intermediate portion of substantially uniform oblong crosssection throughout substantially its entire length, and a tapered portion extending from each terminal portion to said intermediate portion, the larger dimension of said oblong intermediate portion lying in a plane of said elbow section passing through said terminal, intermediate and tapered portions; an assemblage of articulated devices movable through said elbow section, sai-d assemblage including a forward piston unit, a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward piston unit can move out of the other terminal portion.

4. In well apparatus: a ow line including a tubular elbow section having terminal portions at its opposite ends of substantially circular cross-section, an arcuate intermediate portion of substantially uniform oblong crosssection throughout substantially its entire length, and a tapered portion tapering from each end of said intermediate portion to each terminal portion, the larger dimension of said oblong intermediate portion lying in a plane of said oblong section passing through said terminal, intermediate and tapered portions, the smaller dimension of said oblong intermediate portion being substantially equal to the diameter of a terminal portion; Ian assemblage of articulated devices movable through said elbow section, said assemblage including a forward piston unit, a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward piston unit can move out of the other terminal portion.

5. In well apparatus, a ow line including a tubular elbow section having terminal portions at its opposite ends of the same substantially circular cross-section, an arcuate intermediate portion of substantially uniform oblong crosssection throughout substantially its entire length extending along an arc of about 90 degrees, a tapered portion between each terminal portion and said intermediate portion, the large end of said tapered portion conforming to the end of said intermediate portion and the small end of said tapered portion conforming to said terminal portion, the larger dimension of said oblong intermediate portion lying in a plane of said elbow section passing through said terminal, intermediate and tapered portions; an assemblage of articulated devices movable through said elbow section, said assemblage including a forward piston unit, a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward piston unit can move out of the other terminal portion.

6. In well apparatus: a ow line including a tubular elbow section having terminal portions at its opposite ends of the same substantially circular cross-section, an arcuate intermediate portion of substantially uniform oblong cross-section throughout substantially its entire length extending along an arc of about 9() degrees, a tapered portion between each terminal portion and said intermediate portion, the large end of said tapered portion conforming to the end of said intermediate portion and the small end of said tapered portion conforming to said terminal portion, the larger dimension of said oblong intermediate portion lying in a plane of said elbow section passing through said terminal, intermediate and tared portions, the smaller dimension of said oblong intermediate portion being substantially equal to the diameter of said terminal portions; an assemblage of articulated devices movable through said elbow section, siaid assemblage including a forward piston unit, a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward piston unit can move out of the other termin-al portion.

7. In well apparatus: a flow line including a tubular elbow section having terminal portions at its opposite ends of substantially circular cross-section, a curved intermediate portion of substantially uniform oblong cross-section throughout substantially its entire length, and a tapered portion extending from each terminal portion to said intermediate portion, the larger dimension of said oblong intermediate portion lying in a plane of said elbow section passing through said terminal, intermediate yand tapered portions, the curved outer side and the curved inner side of said intermediate portion each having a radius of curvature in cross-section substantially equal to the radius of one of said terminal portions, the sides of said intermediate portion interconnecting said curved inner and outer sides being substantially parallel to each other and spaced apart Ia distance substantially equal to the diameter of said one of said terminal portions; an assemblage of articulated devices movable through said elbow section, said assemblage including a forward piston unit, -a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least las great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward unit can move out of the other terminal portion.

8. In well apparatus: a flow line including a tubular elbow section having terminal portions at its opposite ends of the same substantially circular cross-section, an arcuate intermediate portion of substantially uniform oblong crosssection throughout substantially its entire length extending along an arc of about degrees, a tapered portion between each terminal portion and said intermediate portion, the large end of said tapered portion conforming to the end of s-aid intermediate portion and the small end of said tapered portion conforming to said terminal portion, the larger dimension of said oblong intermediate portion lying in a plane of said elbow section passing through said terminal, intermediate and tapered portions, the curved outer side and the curved inner side of said intermediate portion each having a radius of curvature in cross-section substantially equal to the radius of said terminal portions, the sides of said intermediate portion interconnecting said curved inner and outer sides being substantially parellel to each other and spaced apart a distance substantially equal to the diameter of said terminal portions; an assemblage of articulated devices movable through said elbow section, said assemblage including a forward piston unit, a rearward piston unit, a tool between and pivotally connected to said piston units, said piston units being adapted to slidably seal with the walls of said terminal portions, the overall distance between said units when said assemblage is in said elbow section being at least as great as the distance between said terminal portions, whereby said forward piston unit is in one of the terminal portions before the rearward unit can move out of the other terminal portion.

References Cited UNITED STATES PATENTS CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner. 

